It is intended by means of a device of the above- mentioned type to control the contact pressure between a bobbin maintained in a creel and a roller, which drives the bobbin by friction, so as to follow a course matched to the building of the bobbin.
Such a device is known, for example, from German Patent Publications DE 39 27 142 A1 or DE 195 27 214 A1. With the device in accordance with German Patent Publication DE 39 27 141 A1, the means for generating a torque include an electric motor, whose driving force is transmitted to the creel in the form of a torque by means of a toothed belt drive and rods.
In a device known from German Patent Publication DE 195 27 214 A1, an electric motor generates a torque, which is transmitted to the pivot shaft, and thus to the creel, by means of a belt drive. The belt drive contains one or two belts wound around the driveshaft of the electric motor, which are fastened to the drive shaft and at two fastening points of a transfer lever, which is connected, fixed against relative rotation, with the pivot shaft of the creel. Such a belt drive transmits a torque in a manner almost free of play and hysteresis. Both known devices require an electric motor, whose power or torque is proportional to the current strength applied to it.